Radio Frequency (RF) transmissions are becoming increasingly ubiquitous in today's wirelessly connected world. For instance, cell phone usage is rapidly increasing around the world, high-speed data networks are spreading, and home wireless and wide-area networks are becoming commonplace. In the midst of these and other similar advances, now more than ever, it is crucial that test and measurement instruments provide useful features and interfaces so that an accurate picture of what is happening can be constructed and provided to field personnel such as test engineers and other qualified technicians.
RF carrier signals can transmit information in a variety of ways based on variations in the amplitude, frequency, or phase of the carrier. Governments typically apportion radio frequency ranges to be used for different purposes. As a result, certain devices are permitted to operate only within predetermined bands. Such limitations result in ever more complex and efficient methods for adapting to these constraints and abiding by accepted communications standards. For example, many modern transmission systems use frequency hopping and phase modulation to conform to communication standards and to provide improved functionality and interoperability among different devices competing for similar resources.
Because of the complex nature of these signals, it is difficult or impossible to take accurate measurements of certain aspects of these signals using conventional techniques. While some Real Time Spectrum Analyzers (RTSA) are adept at measuring the generalities of RF signals in the frequency-domain, they are lacking in more specific measurement capabilities, particularly in the time-domain. Demodulation and data decode capabilities, and to some extent, limited single-channel measurements, are available in some RTSAs, but such instruments lack the richness of measurement functionality necessary to understand the totality of the RF signals in a rapidly expanding and multifaceted technological field.
In the presence of random burst lengths, frequency hopping algorithms, phase modulation, signal distortions, and other demanding characteristics of RF signals—existing methods of measuring RF signals, particularly in the time-domain, are deficient. Therefore, it is difficult or impossible to diagnose problems in the signal transmissions or to make complete measurements of the signals.